1. Field of the Invention
This invention relates to emergency locking devices for safety belt retractors, and more particularly to those emergency locking devices for preventing the seat belts from being unwound in response to the sudden changes of the withdrawal forces arising in the seat belts wound by the safety belt retractors.
2. Description of the Prior Art
Emergency locking devices of the type disclosed herein have been advantageously used with seats equipped with safety belts in vehicles, aircraft or the like. More specifically, while under normal conditions free unwinding and rewinding of the seat belt with respect to a safety belt retractor are permitted in response to the change of the attitude of a seat occupant, in the event of an emergency, such as the case where the seat occupant is subjected to an unusual load, as during an accident the withdrawal of the safety belt is locked to prevent the seat occupant from jumping out of the seat, whereby both comfortableness under normal conditions and safety in an emergency are satisfied.
Various structures of such emergency locking devices for safety belt retractors have been proposed. Particularly, it is impossible to make these emergency locking devices larger because of restrictions in spaces where they are installed. Therefore, it is preferable that a device for emergency locking can be achieved only by adding a few parts to the inherent structure of a safety belt retractor. Further, the requirement for miniaturization also means trying to make the structure simpler. Moreover, it can be said that the simpler the structure is, the fewer breakdowns occur, and thus the higher the safety becomes. Besides, the simpler structure may simplify operations for assembling such an emergency locking device of a safety belt retractor.